Negative halogen ions for fusion applications (invited)
- Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)
Over the past quarter century, advances in hydrogen negative-ion sources have extended the usable range of hydrogen-isotope neutral beams to energies suitable for large magnetic confinement fusion devices. Recently negative halogen ions have been proposed as an alternative to positive ions for heavy-ion fusion drivers in inertial confinement fusion, because electron accumulation would be prevented in negative-ion beams, and if desired, the beams could be photodetached to neutrals. This article reports an experiment comparing the current density and beam emittance of Cl{sup +} and Cl{sup -} extracted from substantially ion-ion plasmas with that of Ar{sup +} extracted from an ordinary electron-ion plasma, all using the same source, extractor, and emittance scanner. At similar discharge conditions, the Cl{sup -} current was typically 85%-90% of the positive chlorine current, with an e{sup -}/Cl{sup -} ratio as low as 7 without grid magnets. The Cl{sup -} current was as much as 76% of the Ar{sup +} current from a discharge with the same rf drive. The minimum normalized beam emittance and inferred ion temperatures of Cl{sup +}, Cl{sup -}, and Ar{sup +} were similar, so the current density and optical quality of Cl{sup -} appear as suitable for heavy-ion fusion applications as a positive noble gas ion of similar mass. Since F, I, and Br should all behave similarly in an ion source, they should also be suitable as driver beams.
- OSTI ID:
- 20778987
- Journal Information:
- Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 3 Vol. 77; ISSN 0034-6748; ISSN RSINAK
- Country of Publication:
- United States
- Language:
- English
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Negative Halogen Ions for Fusion Applications
Experimental evaluation of a negative ion source for a heavy ionfusion negative ion driver
Related Subjects
ANIONS
ARGON IONS
BEAM EMITTANCE
BEAM-PLASMA SYSTEMS
CATIONS
CHLORINE
CHLORINE IONS
CURRENT DENSITY
CURRENTS
HEAVY IONS
HYDROGEN ISOTOPES
INERTIAL CONFINEMENT
ION BEAMS
ION SOURCES
ION TEMPERATURE
MAGNETIC CONFINEMENT
MAGNETS
PLASMA
RARE GASES
THERMONUCLEAR DEVICES